Some electric motors are driven by multiphase pulse width modulation (PWM) voltages. Driving an electric motor with a PWM voltage creates a large amount of electrical noise, especially when compared with driving an electric motor with a continuous sinusoidal driving voltage. As a result of the electrical noise and parasitic capacitances, voltages build up on the rotor. When the voltage on the rotor becomes large, it may discharge from the rotor to the frame of the electric motor across the bearings. This may damage the bearings and/or the bearing races that retain and guide the bearings relative to the rotor and the frame of the electric motor. The damage to the rotor and bearing races that results from voltage discharge across the bearings may reduce the lifespan of the bearings and cause failure of the electric motor.